Squared planar markers have become a popular method for pose estimation in applications such as autonomous robots, unmanned vehicles and virtual trainers. The markers allow estimating the position of ...a monocular camera with minimal cost, high robustness, and speed. One only needs to create markers with a regular printer, place them in the desired environment so as to cover the working area, and then registering their location from a set of images.
Nevertheless, marker detection is a time-consuming process, especially as the image dimensions grows. Modern cameras are able to acquire high resolutions images, but fiducial marker systems are not adapted in terms of computing speed. This paper proposes a multi-scale strategy for speeding up marker detection in video sequences by wisely selecting the most appropriate scale for detection, identification and corner estimation. The experiments conducted show that the proposed approach outperforms the state-of-the-art methods without sacrificing accuracy or robustness. Our method is up to 40 times faster than the state-of-the-art method, achieving over 1000 fps in 4 K images without any parallelization.
•A system that speed up the detection of squared planar markers•Employ a multiresolution approach to reduce computing time•Temporal information is also considered to reduce computation.•Up to 40 times faster than the state-of-the-art approaches without any parallelization
Background/Objectives
Hospitalization due to acute illness in older patients is often associated with anxiety or depressive symptoms. In these circumstances, given that pharmacologic treatment should ...be avoided to reduce interactions with ongoing medication regimes, psychotherapy techniques should be considered. The purpose of this study was to evaluate the effectiveness of group reminiscence therapy (RT) on the reduction of anxiety and depressive symptoms in acutely hospitalized older patients.
Methods
Controlled and prospective study conducted on the Acute Geriatric Unit of a university hospital. Patients included in the intervention group (RT Group) attended a group session focused on RT, whereas those included in the control group (UC) received usual hospital care. Exclusion criteria were severe cognitive impairment, impossibility to mobilize, and clinical/hemodynamic instability. The intervention was based on a multi‐task daily group session of reminiscence activities. The severity of anxiety (Hamilton Anxiety Rating Scale, HAM‐A), depressive symptoms (15‐item Geriatric Depression Scale, GDS‐15), loneliness (ESTE‐II social loneliness scale), and fear of death (Collet‐Lester scale) was assessed at admission and discharge in both groups.
Results
The intervention was effective in reducing the proportion of patients with anxiety and depressive symptoms during hospitalization. The proportion of patients with moderate–severe anxiety at discharge was 32.1% in the UC and 13.4% in the RT Group (p < 0.001), whereas the proportion of patients with depressive symptoms at discharge was 49.1% in the UC and 19.5% in the RT Group (p < 0.001). The intervention was independently associated with benefits on anxiety levels (RR 2.45, 95% CI 1.83–3.28) and depression (RR 3.71, 95% CI 2.22–6.19) at discharge. No differences were found in loneliness or fear of death.
Conclusions
A group reminiscence activity reduces the proportion of patients with anxiety and depressive symptoms during hospitalization for an acute disease. Absolute changes in both anxiety and depression scores, even though significant, were relatively small.
Fiducial Objects: Custom Design and Evaluation García-Ruiz, Pablo; Romero-Ramirez, Francisco J; Muñoz-Salinas, Rafael ...
Sensors (Basel, Switzerland),
12/2023, Letnik:
23, Številka:
24
Journal Article
Recenzirano
Odprti dostop
Camera pose estimation is vital in fields like robotics, medical imaging, and augmented reality. Fiducial markers, specifically ArUco and Apriltag, are preferred for their efficiency. However, their ...accuracy and viewing angle are limited when used as single markers. Custom fiducial objects have been developed to address these limitations by attaching markers to 3D objects, enhancing visibility from multiple viewpoints and improving precision. Existing methods mainly use square markers on non-square object faces, leading to inefficient space use. This paper introduces a novel approach for creating fiducial objects with custom-shaped markers that optimize face coverage, enhancing space utilization and marker detectability at greater distances. Furthermore, we present a technique for the precise configuration estimation of these objects using multiviewpoint images. We provide the research community with our code, tutorials, and an application to facilitate the building and calibration of these objects. Our empirical analysis assesses the effectiveness of various fiducial objects for pose estimation across different conditions, such as noise levels, blur, and scale variations. The results suggest that our customized markers significantly outperform traditional square markers, marking a positive advancement in fiducial marker-based pose estimation methods.
Environment landmarks are generally employed by visual SLAM (vSLAM) methods in the form of keypoints. However, these landmarks are unstable over time because they belong to areas that tend to change, ...e.g., shadows or moving objects. To solve this, some other authors have proposed the combination of keypoints and artificial markers distributed in the environment so as to facilitate the tracking process in the long run. Artificial markers are special elements (similar to beacons) that can be permanently placed in the environment to facilitate tracking. In any case, these systems keep a set of keypoints that is not likely to be reused, thus unnecessarily increasing the computing time required for tracking. This paper proposes a novel visual SLAM approach that efficiently combines keypoints and artificial markers, allowing for a substantial reduction in the computing time and memory required without noticeably degrading the tracking accuracy. In the first stage, our system creates a map of the environment using both keypoints and artificial markers, but once the map is created, the keypoints are removed and only the markers are kept. Thus, our map stores only long-lasting features of the environment (i.e., the markers). Then, for localization purposes, our algorithm uses the marker information along with temporary keypoints created just in the time of tracking, which are removed after a while. Since our algorithm keeps only a small subset of recent keypoints, it is faster than the state-of-the-art vSLAM approaches. The experimental results show that our proposed sSLAM compares favorably with ORB-SLAM2, ORB-SLAM3, OpenVSLAM and UcoSLAM in terms of speed, without statistically significant differences in accuracy.
Physical rehabilitation plays a crucial role in restoring motor function following injuries or surgeries. However, the challenge of overcrowded waiting lists often hampers doctors’ ability to monitor ...patients’ recovery progress in person. Deep Learning methods offer a solution by enabling doctors to optimize their time with each patient and distinguish between those requiring specific attention and those making positive progress. Doctors use the flexion angle of limbs as a cue to assess a patient’s mobility level during rehabilitation. From a Computer Vision perspective, this task can be framed as automatically estimating the pose of the target body limbs in an image. The objectives of this study can be summarized as follows: (i) evaluating and comparing multiple pose estimation methods; (ii) analyzing how the subject’s position and camera viewpoint impact the estimation; and (iii) determining whether 3D estimation methods are necessary or if 2D estimation suffices for this purpose. To conduct this technical study, and due to the limited availability of public datasets related to physical rehabilitation exercises, we introduced a new dataset featuring 27 individuals performing eight diverse physical rehabilitation exercises focusing on various limbs and body positions. Each exercise was recorded using five RGB cameras capturing different viewpoints of the person. An infrared tracking system named OptiTrack was utilized to establish the ground truth positions of the joints in the limbs under study. The results, supported by statistical tests, show that not all state-of-the-art pose estimators perform equally in the presented situations (e.g., patient lying on the stretcher vs. standing). Statistical differences exist between camera viewpoints, with the frontal view being the most convenient. Additionally, the study concludes that 2D pose estimators are adequate for estimating joint angles given the selected camera viewpoints.
Angelman syndrome (AS) is a neurogenetic disorder characterized by intellectual disability and atypical behaviors. AS results from loss of expression of the E3 ubiquitin-protein ligase UBE3A from the ...maternal allele in neurons. Individuals with AS display impaired coordination, poor balance, and gait ataxia. PIEZO2 is a mechanosensitive ion channel essential for coordination and balance. Here, we report that PIEZO2 activity is reduced in Ube3a deficient male and female mouse sensory neurons, a human Merkel cell carcinoma cell line and female human iPSC-derived sensory neurons with UBE3A knock-down, and de-identified stem cell-derived neurons from individuals with AS. We find that loss of UBE3A decreases actin filaments and reduces PIEZO2 expression and function. A linoleic acid (LA)-enriched diet increases PIEZO2 activity, mechano-excitability, and improves gait in male AS mice. Finally, LA supplementation increases PIEZO2 function in stem cell-derived neurons from individuals with AS. We propose a mechanism whereby loss of UBE3A expression reduces PIEZO2 function and identified a fatty acid that enhances channel activity and ameliorates AS-associated mechano-sensory deficits.
Model-based tracking is an essential task in fields such as Augmented Reality. State-of-the-art approaches rely on the model’s edges, sometimes combined with image keypoints and color. Nevertheless, ...these image features are not considered part of the model but as temporary information discarded every time the tracking process is restarted. This paper proposes a novel approach that employs an enhanced model that combines edges, keypoints, and fiducial markers for robust and real-time tracking. The experiments conducted show that our method outperforms state-of-the-art model-based approaches and suggest that fiducial markers are a good choice for texturing models.
Age-related macular degeneration (AMD) is the leading cause of central vision loss and severe blindness among the elderly population. Recently, we reported on the association of the
gene (encoding ...for δ-sarcoglycan) polymorphisms with AMD. However, the functional consequence of Sgcd alterations in retinal degeneration is not known. Herein, we characterized changes in the retina of the Sgcd knocked-out mouse (KO,
). At baseline, we analyzed the retina structure of three-month-old wild-type (WT,
) and
mice by hematoxylin and eosin (H&E) staining, assessed the Sgcd-protein complex (α-, β-, γ-, and ε-sarcoglycan, and sarcospan) by immunofluorescence (IF) and Western blot (WB), and performed electroretinography. Compared to the WT,
mice are five times more likely to have retinal ruptures. Additionally, all the retinal layers are significantly thinner, more so in the inner plexiform layer (IPL). In addition, the number of nuclei in the KO versus the WT is ever so slightly increased. WT mice express Sgcd-protein partners in specific retinal layers, and as expected, KO mice have decreased or no protein expression, with a significant increase in the α subunit. At three months of age, there were no significant differences in the scotopic electroretinographic responses, regarding both a- and b-waves. According to our data,
has a phenotype that is compatible with retinal degeneration.
Different mechanisms have been suggested for cocaine neurotoxicity, including oxidative stress alterations. Nuclear factor kappa B (NF-κB), considered a sensor of oxidative stress and inflammation, ...is involved in drug toxicity and addiction. NF-κB is a key mediator for immune responses that induces microglial/macrophage activation under inflammatory processes and neuronal injury/degeneration. Although cerebellum is commonly associated to motor control, muscular tone, and balance. Its relation with addiction is getting relevance, being associated to compulsive and perseverative behaviors. Some reports indicate that cerebellar microglial activation induced by cannabis or ethanol, promote cerebellar alterations and these alterations could be associated to addictive-related behaviors. After considering the effects of some drugs on cerebellum, the aim of the present work analyzes pro-inflammatory changes after cocaine exposure. Rats received daily 15 mg/kg cocaine i.p., for 18 days. Reduced and oxidized forms of glutathione (GSH) and oxidized glutathione (GSSG), glutathione peroxidase (GPx) activity and glutamate were determined in cerebellar homogenates. NF-κB activity, CD68, and GFAP expression were determined. Cerebellar GPx activity and GSH/GSSG ratio are significantly decreased after cocaine exposure. A significant increase of glutamate concentration is also observed. Interestingly, increased NF-κB activity is also accompanied by an increased expression of the lysosomal mononuclear phagocytic marker ED1 without GFAP alterations. Current trends in addiction biology are focusing on the role of cerebellum on addictive behaviors. Cocaine-induced cerebellar changes described herein fit with previosus data showing cerebellar alterations on addict subjects and support the proposed role of cerebelum in addiction.
Molecular oxygen is essential for aerobic organisms in order to synthesize large amounts of energy during the process of oxidative phosphorylation and it is harnessed in the form of adenosine ...triphosphate, the chemical energy of the cell. Oxygen is toxic for anaerobic organisms but it is also less obvious that oxygen is poisonous to aerobic organisms at higher concentrations of oxygen. For instance, oxygen toxicity is a condition resulting from the harmful effects of breathing molecular oxygen at increased partial pressures. Reactive oxygen species (ROS) are chemically reactive molecules containing oxygen that are formed as a natural byproduct of the normal metabolism of oxygen and have important roles in cell signaling and homeostasis. However, in pathological conditions ROS levels can increase dramatically. This may result in significant damage to cell structures. Living organisms have been adapted to the ROS in two ways: they can mitigate the unwanted effects through removal by the antioxidant systems and can advantageously use them as messengers in cell signaling and regulation of body functions. Some other physiological functions of ROS include the regulation of vascular tone, detection, and adaptation to hypoxia. In this review, we describe the mechanisms of oxidative damage and its relationship with the most highly studied neurodegenerative diseases.
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